My mower engine is a briggs and Stratton 18.5 and started smoking all of a sudden. Why?

Maybe its under a lot of stress. Check to see if the weed wacker is pregnant.

Bad rings probably.

Its also possible that the carburetor has let gas leak through and into the crankcase. Check to see if the oil is overfull and smells like gas. If it is then you may just need an oil change and a carburetor cleaning.

Maybe its under alot of stress. Check to see if the weed wacker is pregnant.

Poor start for a first post. Your handle is obviously appropriate. Comments like this are not expected or needed.

Did you recently change the oil? If so, are you certain that you used the type and weight oil recommended for the engine by the manufacturer?

Hi,
Maybe it has blown the head gasket and is sucking oil in through that that point.
Peace,
Clarke